Biomedical subjects

H Wang

Publications and source records attributed to H Wang.

At least 1,243 records · Page 69Linked to original sources

PubMed1999

[Molecular cloning of hTRT catalytic domain and its expression in tumors].

OBJECTIVE: To study the expression of hTRT gene in tumors and its significance in cancer diagnosis. METHODS: The expression of hTRT in HeLa cells and PG cells was estimated by RT-PCR and the hTRT cDNA encoding the catalytic domain from HeLa cells were cloned and sequenced. Using in situ hybridization (ISH) techniques, the expression of hTRT mRNA in 54 human tumors were observed and compared with the expression of hTR. RESULTS: hTRT was detected in both HeLa and PG cells. Sequencing showed that the cloned hTRT catalytic domain cDNA was identical with that reported in the literature. hTRT and hTR expressions were detected in 38/46 and 40/46 malignant tumors respectively, while both hTRT and hTR were not detected in 8 benign tumors. CONCLUSION: hTRT was detected in both HeLa and PG cancer cells. hTRT catalytic domains were highly conservative. The expression of hTRT and hTR were both high in malignant tumors and they were strongly correlated. Our results suggest that detection of hTRT was valuable to clinical oncology diagnosis.

Catalytic Domain↗

PubMed1999

[Effects of p21WAF1/CIP1 gene introduction on a human lung cancer cell line with p53 mutation].

OBJECTIVE: To study the effects of p21WAF1/CIP1 gene expression on the biological hehavior of cancer cells with p53 gene mutation. METHODS: Expression of p21 vehicle was constructed and introduced into a human lung cancer cell ling PG with p53 gene mutation, the morphological and growth characteristics of the transfectant were then analysed. The CDK4 and PCNA levels were evaluated and the response to genotoxic agents were observed. RESULTS: The PG cells with mutant p53 were transfected with ectopic p21 gene which resulted in overexpression of p21 (6-fold of the control). The transfectants presented decreased nuclear irregularity and thinner membrane in nuclear atypia, with delayed growth rate and contact growth inhibition. The transfectant also displayed high serum requirement in culture and increased anchorage dependence. Both levels of CDK4 and PCNA were decreased. However, the cisplatin induced cell apoptosis was delayed. CONCLUSIONS: Expression of p21WAF1/CIP1 gene was effective in cancer suppression even in p53 gene mutation. This may have been achieved through lowering of CDK4 or PCNA levels and not involving the apoptosis mechanism. Activation of p21WAF1/CIP1 gene may be considered a bypass for restoration of p53 gene function in cancer cells with p53 gene mutation.

Antineoplastic Agents↗

PubMed1999

[Significance of telomerase activity detection by fine-needle aspiration in patients with breast cancer].

OBJECTIVE: To study the telomerase activity in samples of breast fine-needle-aspiration specimens and to investigate its potential clinical implications. METHODS: Ninety nine fine-needle aspiration specimens from 83 patients with breast cancers, 12 with benign lesions and 4 with breast inflammation, were studied for the presence of telomerase activity by a PCR-based telomere repeat amplification protocol (PCR-TRAP). RESULTS: Among 83 fine-needle aspiration specimens from patients with breast cancer, telomerase activity was detected in 61 of 69 cytologic-positive specimens, 5 of 7 cytologic-suspicious specimens and 4 of 7 cytologic-negative specimens. Sensitivity of telomerase activity detection was 84.3% (70/83); the coincidence rate between telomerase detection and cytologic confirmation was 77.1% (64/83). Of 12 specimens from patients with benign breast lesions, 4 were positive for telomerase activity, but 4 specimens from patients with breast inflammation were all negative. The Combined use of cytological and telomerase detection can improve the detection rates from 83.1% (69/83) to 93.9% (78/83). CONCLUSION: Detection of telomerase in breast tissue samples by fine-needle aspiration is a sensitive and specific method, which implies that it would be helpful in preoperative cytological diagnosis of breast cancer.

Biopsy, Needle↗

PubMed1999

[Expression of antisense telomerase genes suppressing human cancer malignant phenotypes].

OBJECTIVE: Altering the expression of telomerase genes hTRT and hTR to induce changes in cancer cell biology and to determine their value in cancer gene therapy. METHODS: By genetic transfection of antisense hTRT into HeLa cells, and treatment of PG cells with antisenes hTR oligonucleotides, their effects on cancer cell growth and malignant phenotypes were analyzed. RESULTS: The vehicle for eukaryotic expression of hTRT antisense was constructed and transfected into HeLa cells. The obtained transfectants T4, T5 that could produce antisense hTRT stablely showed marked decrease in growth, with an arrest rate of 24%; the presence of contact growth inhibition was obvious; in nude mice transplantation, the rate for tumor induction was decreased from 100% to 25% or 0%; histologically, the tumor cells from inoculation of transfectant showed less nuclear chromatins and fewer giant tumor cells than those of the parent HeLa cells;the expression of PCNA was significantly reduced in the transfected cells. Treatment of antisense hTR oligonucleotides inhibited PG cell growth at a rate of 8%. CONCLUSIONS: Antisense expression of telomerase genes could significantly suppress cancer cell growth, decrease malignant phenotypes and histological atypia. Therefore, altering expression of telomerase genes may be a new pathway for cancer therapy.

Animals↗

PubMed1999

[Effects of tea polyphenols on microcirculation and antioxidation in aircrew].

OBJECTIVE: To study the effects of tea polyphenols (TP) on bulbi conjunctiva microcirculation (BCM) and antioxidation in aircrew and find out the proper antioxidant for the health protection of aircrew. METHOD: Fourty healthy aircrew were divided into TP group (TP 600 mg/d.po) and control group (placebo) randomly. The effects of TP on microcirculation and antioxidation in aircrew were tested after 20 days. RESULT: Red blood cell (RBC) superoxide dismutase (SOD) activity and GSH-PX (Whole blood glutathione peroxidase)/MDA (serum malondialdehyde) ratio in TP group were significantly higher than those in control (P<0.01), and serum MDA level was significantly decreased after TP administration (P<0.05). The numbers of capillaries and blood flow in micrangium were significantly increased, RBC aggregation, ischemia area and A (arteriole)/V (venule) ratio were remarkably decreased in TP group (P<0.01). The total integral value of microcirculation in TP group was significantly reduced in comparison with that in the control group. CONCLUSION: TP can significantly increase the antioxidative ability of aircrew, decrease the BCM disturbance and improve the microcirculatory function.

Adult↗

PubMed1999

[Determination of isofraxidin in Sarcandra glabra (Thunb.) Nakai by HPLC].

OBJECTIVE: To establish a method for the determination of isofraxidin in Sarcandra glabra. METHOD: Using HPLC with mu-Bondapak C18 column, acetonitrile -0.1% phosphoric acid solution(20:80) as mobile phase and detection wavelength at 344 nm. RESULT: The recovery and RSD were 98.1% and 1.9% (n = 5) respectively. CONCLUSION: This method is rapid, simple and accurate, thus may be used for the quality control of this drug.

Chromatography, High Pressure Liquid↗

PubMed1999

[A study of Bcl-2 expression in normal endometrium and endometrial carcinoma].

To make an initial inquiry into the correlation of development and prognosis with the expression of Bcl-2 protein in endometrial carcinoma, we detected the Bcl-2 protein expression in 40 normal and 60 malignant samples of the endometrium by means of an immunohistochemical technique. We observed that Bcl-2 expression varied with menstrual cycle, becoming stronger in proliferative phase and then declining in secretory phase. Bcl-2 expression in endometrial carcinoma was much weaker than that in normal endometrium, and Bcl-2 was particularly expressed in adenoacanthoma, papillary adenocarcinoma and simple adenocarcinoma. The higher grade and stage were, the stronger Bcl-2 expression was (P < 0.01). In 5 cases of endometrial carcinoma with hyperplastic endometrium, Bcl-2 expression of carcinoma was obviously weaker than that of hyperplastic endometrium. So we conclude that Bcl-2 overexpression may contribute to the formation of hyperplastic endometrium, that obvious reduction of Bcl-2 expression in endometrial carcinoma may promote apoptosis of cells, and that Bcl-2 over-expression may be associated with good prognosis.

Adenocarcinoma↗

PubMed1999

[A study on nasal absorption of psoralen and isopsoralen in Psoralea corylifolia L].

OBJECTIVE: To investigate the nasal absorption regularities of psoralen and isopsoralen of different concentrations. METHOD: Building an experimental model of rat in situ nasal recirculation and determining the contents of psoralen and isopsoralen by HPLC. RESULT: The nasal absorption of psoralen and isopsoralen fitted in with zero order kinetics, getting saturated with the increase of concentration. CONCLUSION: A suitable concentration is necessary for the preparation of nasal remedies psoralen and isopsoralen.

Absorption↗

PubMed1999

[Effects of insulin on synthesis and secretion of apolipoproteins A I, A II, B100, C III and E by cultured HepG2 cells].

This study was intended to observe the effects of insulin on synthesis and secretion of apolipoproteins by hepatic cells. The HepG2 cells were cultured in RPMI 1640 media with bovine insulin (1 microgram/ml media and 10 micrograms/ml media) for 72 hours, and the apolipoproteins contents in cultured media were measured by radioimmunodiffusion assay (RID) kits developed by authors' research laboratory. 40 fold lyophilizely condensed culture media were used for the assays. The results showed that the relative amounts of apo A I, A II, B100, C III and E secreted by HepG2 cells detected by this method were 824 +/- 27, 813 +/- 24, 4875 +/- 82, 597 +/- 74 and 97 +/- 4 ng/mg cell protein, respectively. When 1.0 microgram/ml medium of bovine insulin was added into the culture media, apo A I and apo E secretion remained unchanged. When compared with the control, while apo A II tended to decrease, apo C III tended to increase, and apo B100 secretion decreased by 21.2%; when 10.0 micrograms/ml medium of insulin was added, apo A I, A II and B100 secretion decreased by 6.9% (P < 0.05), 44.3% (P < 0.01) and 29.3% (P < 0.01) respectively, while apo C III secretion increased by 51.8% (P < 0.01). These results support certain parts of the hypothesis of pathogenesis of Chinese endogenous hypertriglyceridemia proposed by Bing-Wen Liu.

Apolipoprotein A-I↗

PubMed1999

[Role of apoptosis and bcl-2 gene in the temporomandibular joint development].

OBJECTIVE: Apoptosis involving in embryogenesis and organ formation has been verified, but the possible roles of apoptosis and its related regulative genes have not been clarified. Temporomandibular joint dysfunction (TMD) has increased in incidence and occurred increasingly in young patients. Thus, research on the development and gene modulation is necessary. METHODS: Tdt-mediated dUTP nick end labeling (TUNEL) and mRNA in situ hybridization were used in observation of apoptosis and bcl-2 gene expression in TMJ of SD rats during prenatal and postnatal developmental period. RESULTS: Apoptosis involved in different development periods of condylar cartilage, and the cells of apoptosis mainly located in the proliferative zone and the area between the prehypertrophic zone and the late hypertrophic zone., bcl-2 was expressed in chondrocytes throughout condylar cartilage with high levels in proliferative and prehypertrophic chondrocytes and obvious low levels in the late hypertrophic chondrocytes. Very few matured chondrocytes expressed bcl-2. CONCLUSION: Apoptosis regulated by bcl-2 plays an important role in prenatal and postnatal development of TMJ.

Animals↗

PubMed1999

[One-time operation in infant cleft lip and palate plus alveolar process].

OBJECTIVE: To improve safety and viability of one-time operation in the therapy of cleft lip and palate and cleft alveolar process. METHODS: Under the air-vein anesthesia, one-time operations were performed in 42 patients with complete cleft lip and palate plus cleft alveolar process. After rehabilitation in ICU, all patients were put into wards, and left hospital 4-7 days after operation. RESULTS: The situation during anesthesia and operation was good. There were no statistically significant changes in blood pressure, oxygen saturation of blood, heart rate and cardiac rhythm before, during and after operation. No anesthetic accident and no complication happened. The loss of blood was about 42.7 +/- 6.5 ml and the duration of operation was about 139.2 +/- 18.6 minutes. The rehabilitation was successful after operations. First intention took place in almost all patients' incisions, and palatal fistulas appeared in only 2 cases. CONCLUSION: Under the control of provisioned pediatric anesthesia and rehabilitation, one-time complete cleft lip and palate plus cleft alveolar process closure is safe and viable.

Alveolar Process↗

PubMed1999

[Partial gene clone and nif gene homologous sequence analysis of Streptococcus sanguis].

OBJECTIVE: To analyze the sequence of Streptococcus sanguis chromosome which contains one DNA fragment of 800 base pairs (bp) and discuss Streptococcus sanguis biological features of heredity. METHODS: Streptococcus DNA of 800-bp genetic fragment was cloned and analyzed by using eukaryotic expression vector. RESULTS: By Genbank database, it showed that the 800-bp genetic sequence was highly homologous with other bacterial nifS and nifU gene, and the highest homologous score was 114. CONCLUSION: This nif gene of ATCC 10556 strain may correlate with nutrient metabolism and peroxide hydrogen release of Streptococcus sanguis.

Cloning, Molecular↗

PubMed1999

[Analysis of 413 cases of mandibular fractures].

OBJECTIVE: To investigate the characteristics of mandibular fracture. METHODS: 413 patients with mandibular fracture were chosen from patients who received treatment at the department of oral and maxillofacial surgery, College of Stomatology, West China University of Medical Sciences from 1986 to 1995, and a retrospective study was carried out. Chi-square test, t-test and linear regression were used to analyzed age, sex, causes, anatomic site, complicated injury, and treatment of jaw fracture. RESULTS: Fracture of Mandible occurred mainly in male, and during 20 to 29 years old. Mental fracture was common in mandibular fracture, and fracture of central craniofacial bone and craniocerebral injury were often complicated with jaw fracture. CONCLUSION: Mandibular fractures are caused mainly by traffic ever since 1990, and rigid intrafixation is a satisfactory treatment which has been accepted by surgeons.

Accidents, Traffic↗

PubMed1999

[Internal fixation for zygomatic arch fracture with super-high molecular weight poly D, L-lactic acid mini-plates and screws: a study in dogs].

OBJECTIVE: To investigate the internal fixation effects of super high molecular weight (Mv = 6.0 x 10(5) kD) poly D, L-lactic acid(PDLLA) mini-plates and screws. METHODS: 10 dogs were utilized in this experiment with the self-contrast study method, comparing with the titanium mini-plates and screws. RESULTS: The mechanical properties of the PDLLA mini-plates and screws appeared to be sufficient to enable undisturbed healing of depressed zygomatic arch fracture. CONCLUSION: The good fixation effect of PDLLA mini-plates and screws was as same as that of the titanium mini-plates and screws without the need of secondary operation.

Animals↗

PubMed1999

[Tissue reaction and degradation of super-high molecular weight poly D, L-lactic acid mini-plates and screws: an animal experiment].

OBJECTIVE: To investigate the tissue reaction and degradation processes of the super-high molecular weight(Mv = 6.0 x 10(5) kD) poly D, L-lactic acid(PDLLA) mini-plates and screws through the internal fixation for zygomatic arch fracture. METHODS: It was carried out by the self-contrast study method and comparing with the titanium mini-plates and screws. RESULTS: There was no side-effects on bone healing. The reaction of soft and hard tissues to PDLLA mini-plates and screws was similar to that of the titanium mini-plates and screws. No complication had been seen with the use of PDLLA mini-plates and screws, including infection, foreign body reaction and underlying osteolysis. The PDLLA devices had no changes in shape after 3 months, and then became the grains in different sizes after 6 months, and were completely resorbed within 12 months in vivo. CONCLUSION: The super-high molecular weight PDLLA mini-plates and screws has good biocompatibility and proper degradation time. It is safe and effective to use the mini-plates and screws made of the super-high molecular weight PDLLA for internal fixation of bone.

Animals↗

PubMed1999

[Determination of major expansion properties of refractory die material compatible with slip casting core of sintered titanium powder].

OBJECTIVE: To determinate major expansion properties of refractory die material. METHODS: The setting expansion ratio of refractory die material for slip casting core of sintered titanium powder at room temperature was performed, as well as thermal expansion ratio from room temperature to 800 degrees C. RESULTS: The maximum setting expansion ratio in 2 hours reached 0.3407%; The final setting expansion ratio in 24 hours was 0.3117%; The mean thermal expansion coefficient was mainly in range of 8 x 10(-6)-11 x 10(-6)/degree C; The expansion property seemed very stable after sintering repeatedly and the small shrinkage after sintering could be compensated with the die spacer and setting expansion. CONCLUSION: The expansion properties of the refractory die material that we synthesized can fulfil the application requirements of slip casting core of sintered titanium powder.

Crowns↗

PubMed1999

[Determination of normal temperature properties of refractory die material compatible with slip casting core of sintered titanium powder].

OBJECTIVE: The refractory die is the precondition for developing slip casting core of sintered powder. This study is to determine the normal temperature properties of the refractory die material compatible with slip casting core. METHODS: to mix the die material at five different ratios (8/1, 7.5/1, 7/1, 6.5/1, and 6/1) and measure their solidification time with self-manufactured Vicker's needle; to prepare five cylindrical specimens (phi 10 x 15 mm) in different drying time for determining their compressive strength, and then to let another five specimens fire at 1000 degrees C four times for measuring the residual compressive strength at room temperature. RESULTS: The setting time was 16.25 minutes (7.5/1), and the lower the powder-liquid ratio, the longer the setting time. The normal compressive strength was 25.32 MPa (drying 24 hours), while the longer the drying time, the higher the compressive strength achieved (P < 0.01). The residual compressive strength was 24 MPa. CONCLUSION: The normal temperature properties of the refractory die material meet the demand of slip casting core of sintered powder.

Compressive Strength↗

PubMed1999

[Effect of ear-canal air pressure variation on tempanometry using a sweep-frequency probe tone].

OBJECTIVE: By observing the effect of ear-canal pressure variation (ECPV) on tempanometry using a sweep-frequency probe tone, the roles of sweep-frequency tempanograms changes were studied. METHOD: Tympanograms using a sweep-frequence probe tone were measured for 60 ears of 30 subjects at ECPV by admittance (Y), susceptance (B), conductance (G) with GSI33 middle ear analyzer. RESULT: There was not obviously difference about phase angle and resonance frequency among 3 measured conditions (P > 0.05); Resonance frequency became higher with higher positive pressure and lower with lower negative pressure in ear-canal; delta Y, delta G got lower with higher positive and lower negative pressure at resonance frequency; delta B is about 0 mmhos and almost didn't change with ECPV; phase angle decreased with higher positive or lower negative pressure. delta Y, delta G and delta phi were the highest at the peak pressure. CONCLUSION: The higher the ear-canal positive pressure or the lower the negative pressure is, the higher the compliance and the lower the mass of middle ear is comparatively. The rub of middle ear is the lowest at normal peak pressure.

Acoustic Impedance Tests↗